This application claims the benefit of French Patent Application No. 99 07355, filed Jun. 10, 1999, entitled Benzopyrans Annelated In C7-C8 With An Aromatic Heterocycle And Compositions And (Co)Polymer Matrices Containing Them, by Olivier Breyne, You-Ping Chan and Patrick Jean.
The present invention relates to novel benzopyran-type compounds which are annelated in C5-C6 and C7-C8 and which have, in particular, photochromic properties. The invention also relates to photochromic compositions and photochromic ophthalmic articles (lenses for example) which contain said benzopyrans. The invention also covers the preparation of these novel compounds.
The photochromic compounds are capable of changing colour under the influence of a poly- or mono-chromatic light (UV for example) and of returning to their initial colour when the luminous irradiation ceases, or under the influence of temperature and/or a poly- or mono-chromatic light different from the first.
The photochromic compounds find applications in various fields, e.g. for the manufacture of ophthalmic lenses, contact lenses, solar protection glasses, filters, camera optics or photographic apparatus optics or other optical devices and observation devices, glazing, decorative objects, bill elements or even for information storage by optical inscription (coding).
In the field of ophthalmic optics, and in particular the spectacles trade, a photochromic lens which comprises one or more photochromic compounds must have:
a high transmission in the absence of ultraviolets,
a low transmission (high colourability) under solar irradiation,
adapted coloration and discoloration kinetics,
a tint acceptable to the consumer (grey or brown preferably) with preferably a maintenance of the chosen tint during the coloration and the discoloration of the lens,
a maintenance of the performances, the properties, within a temperature range of 0-40xc2x0 C.,
a significant durability, since these objectives sought after are sophisticated corrective lenses and therefore expensive.
These lens characteristics are in fact determined by the active photochromic compounds which they contain; compounds which must furthermore be perfectly compatible with the organic or inorganic support which constitutes the lens.
Moreover, it is to be noted that obtaining a grey or brown tint may necessitate the use of at least two photochromes of different colours, i. e. having distinct maximal absorption wavelengths in the visible. This combination further imposes other requirements of the photochromic compounds. In particular, the coloration and discoloration kinetics of the (two or more) combined active photochromic compounds must be essentially identical. The same applies for their stability with time and also for their compatibility with a plastic or inorganic support.
Amongst the numerous photochromic compounds described in the prior art, benzopyrans and naphthopyrans may be cited which are described in patents or patent applications U.S. Pat. Nos. 3,567,605, 3,627,690, 4,826,977, 5,200,116, 5,238,981, 5,411,679, 5,429,744, 5,451,344, 5,458,814, 5,651,923, 5,645,767, 5,698,141, 5,783,116, WO-A-95 05382, FR-A-2,718,447, WO-A-96 14596, and WO-A-97 21698, which are of the reduced formulae below: 
Certain patents (e.g. EP-A-562 915, FR-A-2,718,447, U.S. Pat. No. 5,604,280, WO-A-95 05382, U.S. Pat. Nos. 5,429,774 and 5,411,679) relate more specifically to benzopyrans which are annelated with aromatic heterocycles. US patent U.S. Pat. No. 5,411,679 notably claims the general structure below: 
in which ring A is a substituted or non-substituted benzothieno- or benzofurano-type heterocycle, annelated in position 2,3 or 3,2 with sides f, g or h. In the case of the compounds in which A is fused on side h, y and z are equal to zero in the examples described and the discoloration kinetics are slow.
These compounds claim to satisfy the specifications defined above. In reality, if these compounds really do have one or more of the basic properties sought after, such as a high transmission in the absence of ultraviolets and a high colourability under solar irradiation, none of the compounds described hitherto have the complete combination of the properties sought after which are necessary for the production of satisfactory articles. In particular, none of these compounds is intrinsically grey or brown and the necessity of using an additional photochrome in order to obtain one of these two tints does subsist.
In this context, it is to the credit of the inventors for having been interested in this type of derivative as a base for developing novel photochromes, and for having proposed a novel family of molecules which have particularly advantageous photochromic properties.
Thus, according to a first of its aspects, the present invention relates to compounds of formula (I): 
in which:
A is an aromatic heterocycle of the thieno, benzothieno, furano, benzofurano, pyrrolo, indolo, naphthofurano or naphthothieno type, said heterocycle being fused with the benzopyran in positions 2,3 or 3,2;
R1 and R2, which are identical or different, represent, independently:
hydrogen,
a linear or branched alkyl group comprising 1 to 12 carbon atoms,
a cycloalkyl group comprising 3 to 12 carbon atoms,
an aryl or heteroaryl group comprising in its basic structure 6 to 24 carbon atoms or 4 to 24 carbon atoms respectively and at least one heteroatom selected from sulphur, oxygen and nitrogen; said basic structure being optionally substituted with at least one substituent selected from the whole of the substituents given below:
a halogen, and notably fluorine, chlorine and bromine,
a hydroxy,
a linear or branched alkyl group comprising 1 to 12 carbon atoms,
a linear or branched alkoxy group comprising 1 to 12 carbon atoms,
a haloalkyl or haloalkoxy group corresponding to the (C1-C12) alkyl or alkoxy groups above respectively which are substituted with at least one halogen atom, and notably a fluoroalkyl group of this type,
a linear or branched alkenyl group comprising 2 to 12 carbon atoms, and notably a vinyl group or an allyl group,
an xe2x80x94NH2 group,
an xe2x80x94NHR group, R representing a linear or branched alkyl group comprising 1 to 6 carbon atoms,
a 
xe2x80x83group, Rxe2x80x2 and Rxe2x80x3, which are identical or different, representing independently a linear or branched alkyl group comprising 1 to 6 carbon atoms or representing together with the nitrogen atom to which they are bound a 5- to 7-membered ring which can comprise at least one other heteroatom selected from oxygen, sulphur and nitrogen, said nitrogen being optionally substituted with an Rxe2x80x2xe2x80x3 group, which is a linear or branched alkyl group comprising 1 to 6 carbon atoms,
a methacryloyl group or an acryloyl group,
an aralkyl or heteroaralkyl group, the alkyl group, which is linear or branched, comprising 1 to 4 carbon atoms and the aryl part of which has the same definition as that given supra for the aryl and heteroaryl group;
xe2x80x83or said two substituents R1 and R2 together form an adamantyl, norbornyl, fluorenylidene, di(C1-C6)alkylanthracenylidene or spiro(C5-C6)cycloalkylanthracenylidene group ; said group being optionally substituted with at least one of the substituents listed above for R1, R2: an aryl or heteroaryl group;
R3 and R4, which are identical or different, represent, independently:
a halogen, and notably fluorine, chlorine or bromine,
a hydroxy,
a linear or branched alkyl group comprising 1 to 12 carbon atoms (advantageously 1 to 6 carbon atoms),
a cycloalkyl group comprising 3 to 12 carbon atoms,
a linear or branched alkoxy group comprising 1 to 12 carbon atoms (advantageously 1 to 6 carbon atoms),
a haloalkyl, halocycloalkyl, or haloalkoxy group corresponding to the alkyl, cycloalkyl, alkoxy groups above respectively, which are substituted with at least one halogen atom, notably selected from fluorine, chlorine and bromine,
an aryl or heteroaryl group having the same definition as that given supra for R1, R2,
an aralkyl or heteroaralkyl group, the alkyl group, which is linear or branched, comprising 1 to 4 carbon atoms, and the aryl and heteroaryl groups having the same definitions as those given supra for R1, R2,
an amine or amide group: xe2x80x94NH2, xe2x80x94NHR, xe2x80x94CONH2, xe2x80x94CONHR, 
xe2x80x83R, Rxe2x80x2, Rxe2x80x3 having their respective definitions given supra for the amine substituents of the values R1 , R2: aryl or heteroaryl,
an xe2x80x94OCOR6 or xe2x80x94COOR6 group, R6 representing a straight or branched alkyl group comprising 1 to 6 carbon atoms, or a cycloalkyl group comprising 3 to 6 carbon atom""s, or a phenyl group, optionally substituted with at least one of the substituents listed above for the values of R1, R2: aryl or heteroaryl;
xe2x80x83or
at least two of the R3 groups, which are adjacent, form a 5- to 6-membered aromatic or non-aromatic ring which can comprise at least one heteroatom selected from the group comprising oxygen, sulphur or nitrogen and/or at least one substituent selected from a C1-C6 alkyl group which is linear or branched, a C1-C6 alkoxy group which is linear or branched, and an amine group of formula xe2x80x94NH2, xe2x80x94NHR or 
xe2x80x83as defined above, as substituent, of the basic structure of the aryl or heteroaryl group representing R1 or R2; and
m and n are integers of 0 to 4.
The person skilled in the art will obviously have understood that the branched alkyl, alkoxy and alkenyl groups, as defined above, comprise a sufficient number of carbon in order to be branched (i.e. more than 3, more than 3, and more than 4 carbon atoms respectively).
The compounds of the inventionxe2x80x94annelated benzopyrans of formula (I)xe2x80x94have very fast discoloration kinetics.
Amongst said compounds of the invention, preferred are those which have the formula (I) in which:
R1, R2 are identical or different and represent independently optionally substituted aryl or heteroaryl groups the basic structure of which is selected from the group comprising phenyl, naphthyl, biphenyl, pyridyl, furyl, benzofuryl, dibenzofuryl, Nxe2x80x94(C1-C6)alkylcarbazole, thienyl, benzothienyl, dibenzothienyl and julolidinyl groups ; R1 and/or R2 representing, advantageously, a para-substituted phenyl group;
xe2x80x83or
R1 and R2 together form an adamantyl or norbornyl group;
R3 represents a halogen, an alkyl group or an alkoxy group ; and
n=0 and m=1.
According to a second of its aspects, the present invention relates to a method of preparation of the compounds (I), characterised in that it consists essentially of carrying out a condensation:
of an intermediate product of formula (II) given below: 
xe2x80x83in which A, R3, R4, m and n are as defined above with reference to formula (I),
with a derivative of propargylic alcohol, having formula (III) below: 
xe2x80x83in which R1 and R2 are as defined supra with reference to formula (I);
the condensation (II)/(III) being carried out advantageously in the presence of a catalyst, this catalyst being preferably selected from the group comprising para-toluenesulphonic acid, dodecylsulphonic acid or bromoacetic acid;
xe2x80x83or
with an aldehyde derivative, having formula (IIIxe2x80x2) below: 
xe2x80x83in which R1 and R2 are as defined supra with reference to formula (I);
the condensation (II/(IIIxe2x80x2) being carried out, advantageously, in the presence of a metallic complex, preferably a complex of titanium, titanium (IV) ethoxide being particularly preferred.
In practice, the condensation reaction between compounds (II) and (IIIxe2x80x2) can take place in solvents such as toluene, xylene or tetrahydrofuran, to which appropriate catalysts are optionally added. For more details on the condensation of compounds (II), (IIIxe2x80x2), reference may be made to the EP-A-0 562 915 patent application.
The compounds of formula (III) are known to the person skilled in the art and are obtained from the corresponding ketone according to a method described notably in the WO-A-96 14596 patent application. The ketone is itself commercial or is prepared according to the known methods such as the Friedel Crafts method (cf. WO-A-96 14596 and cited references).
Aldehydes (IIIxe2x80x2), which are derivatives of (III), are obtained by rearrangement in an acid medium (cf. J. Org. Chem., 1977, 42, 3403).
The compounds of formula (IIa) and (IIb) (compounds of formula (II) in which the heterocycle is annelated in 2,3 or 3,2 respectively) are obtained according to a synthetic scheme the various steps of which are adaptations of known methods. The preferred general synthesis scheme is given below: 
In a first sequence, tetralone (IV) is converted into tetralone (V) according to known methods (cf. WO 96/38435 and U.S. Pat. No. 3,980,699).
The action of two equivalents of organolithium (VIa) (cf. The Chemistry of Heterocycles, Stuttgart; New York: Thieme, 1995) or (VIb) (cf. J. Chem. Soc. (C) 1971, 3447-3454) leads to compounds (VIIa) and (VIIb) respectively which are dehydrated to give mixtures (VIIIa)+(IXa) and (VIIIb)+(IXb) respectively. These compounds are then cyclised to give (IIa) and (IIb) respectively in phosphoric acid. The cyclisation giving (IIa) and (IIb) in phosphoric acid can also be carried out on compounds (VIIa) and (VIIb).
According to a third of its aspects, the invention also relates to the novel intermediate products of formula (II) recalled below: 
in which A, R3, R4, m and n are as defined supra with reference to formula (I).
According to a fourth of its aspects, the object of the invention is (co)polymer(s) and/or reticulate(s) obtained by polymerising and/or cross-linking and/or grafting at least one monomer consisting of a compound (1) as defined above. Thus, the compounds (I) according to the invention can be per se (co)monomers and/or be comprised in (co)polymerisable and/or cross-linkable (co)monomers. The (co)polymers and/or reticulates thus obtained can constitute photochromic matrices such as those presented infra.
According to a fifth of its aspects, the present invention relates to the use of said compounds of formula (I) of the invention as photochromic agents. Another object of the invention is, therefore:
firstly, novel photochromic compounds which are constituted by the C7-C8-annelated benzopyran derivatives such as defined above, taken alone or in a mixture of themselves and/or with at least one other photochromic compound of another type and/or with at least one non-photochromic colouring agent;
secondly, novel photochromic compositions which comprise at least one compound (I) as defined above, and/or at least one linear or cross-linked (co)polymer containing at least one compound (I) according to the invention in its structure. Such photochromic compositions can contain at least one other photochromic compound, of another type and/or at least one non-photochromic colouring agent and/or at least one stabilising agent. These photochromic compounds of another type, non-photochromic colouring agents, and stabilising agents are prior art products known to the person skilled in the art.
Within the context of the present invention, combinations of photochromic compounds of the invention and/or combinations of photochromic compounds of the invention and photochromic compounds of another type according to the prior art are particularly recommended; such combinations being interesting in that they are suitable for generating grey or brown tints, which are desired by the public in applications such as ophthalmic spectacles or solar spectacles. These additional photochromic compounds can be those known to the person skilled in the art and described in the literature, e.g. chromenes (U.S. Pat. Nos. 3,567,605, 5,238,981, WO-A-94 22850, EP-A-0 562 915), spiropyrans or naphthospiropyrans (U.S. Pat. No. 5,238,981) and spiroxazines (Crano et al., xe2x80x9cApplied Photochromic Polymer Systemsxe2x80x9d, Ed. Blackie and Son Ltd, 1992, chapter 2).
Said compositions according to the invention can also comprise:
non-photochromic colouring agents which enable adjusting the tint,
and/or one or more stabilising agents, such as an anti-oxidising agent for example,
and/or one or more anti-UV,
and/or one or more anti-radicals,
and/or one or more photochimic excited state deactivators.
These additives can notably enable improving the durability of said compositions.
The compounds of the invention envisaged within the context of their photochromic applications can be used in solution. Thus, a photochromic solution can be obtained by dissolving at least one of said compounds in an organic solvent such as toluene, dichloromethane, tetrahydrofuran or ethanol. The solutions obtained are in general colourless and transparent. When exposed to sunlight, they develop a strong coloration and regain the colourless state when they are placed in an area of less exposure to the sun""s rays or, in other words, when they are no longer submitted to UV. In general, a very low concentration of product (of the order of 0.01 to 5% by weight) is sufficient to obtain an intense coloration.
The compounds according to the invention are furthermore compatible with support matrices of organic polymer or of inorganic material (even of an inorganic-organic hybrid material), in a form included in said matrices as well as in the form of a coating of said matrices.
Also, within the context of the fifth aspect of the invention in relation to the photochromic applications, the object of the invention is a matrix which comprises:
at least one compound (I), as defined supra;
and/or at least one (co)polymer and/or reticulate, as defined supra;
and/or at least one composition, as presented above.
The most interesting applications of the compounds of the invention are in fact those in which the photochrome is dispersed uniformly within or on the surface of a matrix formed by a polymer and/or copolymer and/or mixture of (co)polymers.
Following the example of their behaviour in solution, the compounds (I), included in a polymer matrix are colourless or slightly coloured in the initial state and rapidly develop an intense coloration under a UV light (365 nm) or under a light source of the solar type. Finally, they regain their initial coloration once the irradiation ceases.
The methods of implementation which can be envisaged in order to obtain such a matrix are very varied. Amongst those known to the person skilled in the art, the diffusion in the (co)polymer, from a suspension or solution of the photochrome, in a silicone oil, in an aliphatic or aromatic hydrocarbon, or in a glycol, or from another polymer matrix, can be cited for example. The diffusion is commonly carried out at a temperature of 50 to 200xc2x0 C. for a period of time of 15 minutes to several hours, according to the nature of the polymer matrix. Another implementation technique consists in mixing the photochrome in a formulation of polymerisable materials, depositing this mixture on a surface or in a mould, and then carrying out the copolymerisation. These implementation techniques, and others, are described in the article by Crano et al. xe2x80x9cSpiroxazines and their use in photochromic lensesxe2x80x9d published in Applied Photochromic Polymer Systems, Ed. Blackie and Son Ltd -1992.
The following products may be mentioned as examples of preferred polymer materials for forming matrices which are useful in optical applications of the photochromic compounds according to the invention:
alkyl, cycloalkyl, (poly or oligo)ethylene glycol, aryl or arylalkyl poly(mono-, di- tri- or tetra)acrylate or poly(mono-, di-, tri- or tetra)methacrylate, which is optionally halogenated or which comprises at least one ether and/or ester and/or carbonate and/or carbamate and/or thiocarbamate and/or urea and/or amide group,
polystyrene, polyether, polyester, polycarbonate (e.g. bisphenol-A polycarbonate, diallyl diethylene glycol polycarbonate), polycarbamate, polyepoxy, polyurea, polyurethane, polythiourethane, polysiloxane, polyacrylonitrile, polyamide, aliphatic or aromatic polyester, vinylic polymers, cellulose acetate, cellulose triacetate, cellulose acetate-propionate or polyvinylbutyral,
those obtained from difunctional monomers having the formula below: 
xe2x80x83in which:
R10, Rxe2x80x210, R11 and Rxe2x80x211 are identical or different and represent independently a hydrogen or a methyl group;
m1 and n1 are, independently, integers between 0 and 4 (inclusive) ; and are advantageously independently equal to 1 or 2;
X and Xxe2x80x2, which are identical or different, are a halogen and represent, preferably, a chlorine and/or a bromine;
p1 and q1 are, independently, integers between 0 and 4 (inclusive);
copolymers of at least two types of copolymerisable monomers selected from the precursor monomers of the polymers listed supra, and preferably those belonging to the groups comprising: (meth)acrylic monomers, vinylic monomers, allylic monomers, and mixtures thereof
In a particularly preferred manner, the photochromes of the invention are used with resins which have a nanobiphasic structure and which are obtained by copolymerising at least two different, specific difunctional monomers. Such resins have been described by the Applicant in the French patent Application FR-A-2,762,845 and International patent Application WO-A-98 504 43.
The amount of photochrome used in the (co)polymer matrix depends upon the degree of darkening desired. Usually, between 0.001 and 20% by weight of it is used.
Still according to the fifth of its aspects in relation to the applications of the compounds (I) as photochromes, another object of the present invention is ophthalmic articles, such as ophthalmic or solar spectacle articles, comprising:
at least one compound (I) according to the invention,
and/or at least one (co)polymer and/or reticulate formed, at least in part, from compound(s) of the invention,
and/or at least one photochromic composition as defined above,
and/or at least one matrix (as defined supra), of an organic polymer material or of an inorganic material, or even of a hybrid inorganic-organic material, said matrix initially comprising at least one compound of the invention.
In practice, the articles which are more particularly covered by the present invention are ophthalmic lenses or photochromic solar lenses, glazing (windows for buildings, for locomotion engines, automobile vehicles), optical devices, decorative articles, solar protection articles, information storage, . . .
The present invention is illustrated by the Examples which follow of synthesis and of photochromic validation, of compounds of the invention.